Abstract
Hardcore bosons on honeycomb lattice ribbons with zigzag edges are studied using exact numerical simulations. We map out the phase diagrams of ribbons with different widths, which contain superfluid and insulator phases at various fillings. We show that charge domain walls are energetically favorable, in sharp contrast to the more typical occupation of a set of sites on a single sublattice of the bipartite geometry at $\rho=\frac{1}{2}$ filling. This `self-organized domain wall' separates two charge-density-wave (CDW) regions with opposite Berry curvatures. Associated with the change of topological properties, superfluid transport occurs down the domain wall. Our results provide a concrete context to observe bosonic topological phenomena and can be simulated experimentally using bosonic cold atoms trapped in designed optical lattices.
Highlights
One of the most interesting properties of condensed matter systems is their condensation into ordered low-temperature phases, breaking an underlying symmetry of the Hamiltonian
In addition to being manifest as metastable states, domain walls can arise in other ways
In model Hamiltonian studies on “ladder” geometries using the density matrix renormalization group, the charge patterns are found to be “vertical stripes”; i.e., the doped holes lie parallel to the short direction of the cluster [3]
Summary
One of the most interesting properties of condensed matter systems is their condensation into ordered low-temperature phases, breaking an underlying symmetry of the Hamiltonian. In model Hamiltonian studies on “ladder” geometries using the density matrix renormalization group, the charge patterns are found to be “vertical stripes”; i.e., the doped holes lie parallel to the short direction of the cluster [3] These charge patterns are fundamentally connected to magnetism, e.g., the π -phase shift, and to chargedensity-wave (CDW) and d-wave pairing order. We argue that charge domain walls are energetically favorable compared to occupation of a set of sites on a single sublattice of the bipartite geometry, even at half filling This is a rather unique feature compared to situations in which domain walls are excitations rather than the ground state. The low-density sites of the domain wall are arranged “horizontally” (parallel to the long axis), rather than vertically These “self-organized domain walls” open the possibility of superfluid transport down the chain.
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